President Barack Obama and President Lee Myung-bak participate in a press conference at the Blue House in Seoul, Republic of Korea, March 25, 2012. Photo: Chuck Kennedy/The White House

Barack Obama also pledged to work with Russia and China, speaking ahead of a summit in Seoul aimed at reducing the risk of nuclear terrorism. He singled out the US’s position to seek change but added that “serious sustained global effort” was needed, BBC reports.

Speaking few hours before the opening of a nuclear security summit in South Korea, Obama said major progress had been made over the past two years to decrease the number of material that could be used to make thousands of bombs.

“But we’re under no illusions. We know that nuclear material – enough for many weapons – is still being stored without adequate protection,” the President said.

“We know that terrorists and criminal gangs are still trying to get their hands on it, as well as the radioactive material for a dirty bomb… the danger of nuclear terrorism remains one of the greatest threats to global security.”

Mr Obama mentioned, with more than 1,500 deployed nuclear weapons and 5,000 warheads, the United States had “more nuclear weapons than we need”.

“I firmly believe that we can ensure the security of the United States and our allies, maintain a strong deterrent against any threat, and still pursue further reductions in our nuclear arsenal,” he said.

Obama also urged the leaders or top officials from 53 nations gathered for the summit to “keep at it”, and pledged further actions from the United States including efforts with Russia to jointly cut their stockpiles, writes The Jakarta Globe.

The U.S. President told North Korea on Monday to abandon its nuclear ambitions, warning its provocative behavior would not be rewarded.

“By now it should be clear, your provocations and pursuit of nuclear weapons have not achieved the security you seek, they have undermined it,” he said, in what he called a direct address to the North’s new leadership.

“And know this – there will be no more rewards for provocations. Those days are over. This is the choice before you. This is the decision you must make.”

The US president added he was looking forward to meeting newly-elected Russian President Vladimir Putin to discuss further nuclear arms cuts. “I’m confident that, working together, we can continue to make progress and reduce our nuclear stockpiles,” he said.

Mr Obama would seek to follow on from the New Start (Strategic Arms Reduction Treaty) pact he struck in 2010 with the previous Russian leader Dmitry Medvedev.

The New Start deal agreed between Washington and Moscow was intended to replace its lapsed predecessor, Start (Strategic Arms Reduction Treaty). It trims US and Russian nuclear arsenals to 1,550 deployed nuclear warheads – a cut of about 30% from a limit set previously.

In Asia, President said, the US has suggested China should work with Washington and ”that offer remains open”. He warned Pyongyang that its planned long-range missile launch would only increase its isolation.

”You can continue with the road you are on but we know where that leads,” he said, addressing the North Korean leaders directly. ”Today, we say: Pyongyang, have the courage to pursue peace.”

Pyongyang reports it is preparing to launch a long-range missile which it says will put a satellite in orbit. The launch site is in north-western North Korea, not far from the Chinese border.

“We are preparing measures to track the missile’s trajectory and shoot it down if it, by any chance, deviates from the planned route and falls into our territory,” a defence ministry spokesman said.

Speaking to Iran, Mr Obama said there was still time to resolve the impasse over its nuclear programme through diplomacy. “But time is short,” he warned. ”Iran must act with the seriousness and sense of urgency that this moment demands.”

“Today, I’ll meet with the leaders of Russia and China as we work to achieve a resolution in which Iran fulfils its obligations,” Mr Obama continued.

Despite lofty announcements it may prove difficult to achieve significant progress at the summit, says the BBC’s Jonathan Marcus.

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